Recently, hybrid vehicles and electric vehicles using a motor and an inverter are widely used. In order to control the rotation of the motor properly in such fields, it is important to measure a current flowing through the motor.
As a method of measuring such a current, for example, there is a current sensor in which, according to a current applied to a busbar that connects the motor and the inverter, a magnetic field generated around the busbar is detected by a detection element (magnetic sensor) and the current applied to the busbar is calculated based on the detected magnetic field, for example, as disclosed in JP 2009-121864A (Reference 1).
In the current sensor disclosed in Reference 1, the busbar to which the current is applied and a core that concentrates the magnetic field are held in the housing, with the core arranged around the busbar. A predetermined gap is formed in the core, and an element main body of the detection element is arranged in the gap.
The detection element, after having plural connection terminals fixed to a circuit board by soldering or the like, is assembled on both the circuit board and the housing so that the element main body is arranged in the gap.
In the related-art current sensor, the detection element is assembled on both the circuit board and the housing by holding the element main body in the housing after the plural connection terminals are fixed to the circuit board.
Therefore, at the stage where the plural connection terminals are fixed to the circuit board, the attitude of the element main body to the circuit board is restricted. Meanwhile, the circuit board is fixed to the housing, in a predetermined attitude facing the housing.
Therefore, when the element main body is assembled in such a way that the element main body is held in the housing, if there is an error in the attitude of the element main body to the circuit board, an operation to correct the attitude or the like is necessary and it takes time and effort to assemble the detection element on both the circuit board and the housing.
If the assembling accuracy is roughly set by expanding the gap between the core and the element main body in order to facilitate the assembling of the detection element, detection accuracy may fall.
Also, if the assembling accuracy of the element main body to the core is set roughly, the change in the attitude of the element main body to the core caused by temperature change increases because of the difference in the coefficient of thermal expansion between the circuit board and the housing. Detection accuracy may fall for this reason as well.